中文摘要：

目的通过比较不同电离室测量及蒙特卡罗计算结果，研究不同方法对小野数据测量的适用性。方法用不同电离室测量及蒙特卡罗计算瓦里安6MVX线在0．5cm×0．5cm-10cm×10cm射野的总散射因子和百分深度剂量，对测量和计算结果进行比较和分析。结果当射野≥3．5cm×3．5cm时各电离室测量及蒙特卡罗计算结果间差异较小，当射野≤3．0cm×3．0cm时不同结果间差异明显。CC04、CC13电离室适合于≥2．0cm×2．0cm射野的总散射因子和百分深度剂量测量。结论CC04、CC13电离室测量和蒙特卡罗计算方法能确定≥2．0cm×2．0cm射野的总散射因子和百分深度剂量，更小射野测量和计算数据需慎重评估。

英文摘要：

Objective The beam data is compared with those obtained from Monte Carlo （MC） simulation and measurement to investigate their feasibility and reliability for X - ray small fields . Methods The beam data, including the total scatter factor （ Scp ）, percentage depth dose （PDD） was acquired by measurement and calculation with the field size ranging from 0.5cm×0.5cm-10cm×10cm. The results were compared and analyzed. Results All the data is most consistent for the fields size of ≥3.5cm×3.5cm, but they are obvious different for the fields size of ≤3.0cm×3.0cm. The measurements seem to reliable using the chambers of CC04 and CC13 for the fields size of ≥2.0cm×2.0cm. Conclusions It is demonstrated that the accurate measurements and calculations of Sop and PDD can be obtained for the fields size of ≥2.0cm×2.0cm, but they needed more researches for the smaller fields.